Chemical mechanical polishing (CMP) is generally known in the art. For example U.S. Pat. No. 5,177,908 issued to Tuttle in 1993 describes a finishing element for semiconductor wafers, having a face shaped to provide a constant, or nearly constant, surface contact rate to a workpiece such as a semiconductor wafer in order to effect improved planarity of the workpiece. U.S. Pat. No. 5,234,867 to Schultz et al. issued in 1993 describes an apparatus for planarizing semiconductor wafers which in a preferred form includes a rotatable platen for polishing a surface of the semiconductor wafer and a motor for rotating the platen and a non-circular pad is mounted atop the platen to engage and polish the surface of the semiconductor wafer. Fixed abrasive finishing elements are known for polishing. Illustrative examples include U.S. Pat. No. 4,966,245 to Callinan, U.S. Pat. No. 5,823,855 to Robinson, and WO 98/06541 to Rutherford.
An objective of polishing of semiconductor layers is to make the semiconductor layers as nearly perfect as possible. Current finishing elements can suffer from being costly to manufacture. Also current finishing elements for semiconductor wafers have relatively homogenous surfaces which inherently limits their versatility in some demanding finishing applications. Still further, current finishing elements do not have built into their construction a local region of material on their surface which can help reinforce them, prolong their useful life, and also improve finishing performance while also improving manufacturability and versatility. Still further, lack of a continuous phase matrix on their surface can reduce the flexibility to add finishing enhancers. Still further, a lack of the above characteristics in a finishing element reduces the versatility of the finishing method which can be employed for semiconductor wafer surface finishing. Still further, current finishing pads are limited in the way they apply pressure to the abrasives and in turn against the semiconductor wafer surface being finished. These unwanted effects are particularly important and can be deleterious to yield and cost of manufacture when manufacturing electronic wafers which require extremely close tolerances in required planarity and feature sizes.
It is an advantage of this invention to improve the finishing method for semiconductor wafer surfaces to make them as perfect as possible. It is an advantage of this invention to make finishing elements with a lower cost of manufacture and thus also reduce the cost of finishing a semiconductor wafer surface. It is an advantage of this invention develop a heterogeneous finishing element surface having local regions which improve versatility of the finishing elements and the methods of finishing semiconductor wafers which result. It is also an advantage of the invention to develop finishing element having local regions reinforced with a continuous phase material. It is further an advantage of the invention to develop a finishing element having local regions for including finishing enhancers such as finishing aids. It is further an advantage of the invention to develop a finishing element with a new method of cooperating between its elements to improve die planarity, global planarity, and finishing performance. It is an advantage of the invention to develop a finishing element which has a unique way of applying pressure to the unitary discrete finishing member and to the workpiece surface being finished. It is further an advantage of this invention to help improve yield and lower the cost of manufacture for finishing of workpieces having extremely close tolerances such as semiconductor wafers.
These and other advantages of the invention will become readily apparent to those of ordinary skill in the art after reading the following disclosure of the invention. Preferred embodiments have one, preferably two, and even more preferably a multiplicity of the advantages disclosed herein.
A preferred embodiment of this invention is directed to an unitary refining element having a plurality of discrete refining members for refining a semiconductor wafer comprising discrete refining members wherein each discrete refining member has a surface area of less than the surface area of the semiconductor wafer being finished, each discrete refining member has a discrete refining member refining surface and a refining member body, each discrete refining member has a refining surface, each refining member body is comprised of a continuous region of organic synthetic resin, and a ratio of the shortest distance across in centimeters of the discrete refining member body to the thickness in centimeters of each discrete refining member body is at least 10/1; a unitary resilient body comprised of an organic polymer wherein the unitary resilient body has a plurality of discrete refining members attached to the unitary resilient body in such a manner that each discrete refining member is separated in space from its nearest discrete refining member; and the unitary resilient body of organic polymer has a different flexural modulus than the organic synthetic resin in the unitary resilient body.
A preferred embodiment of this invention is directed to a method of buffing a semiconductor wafer surface with a unitary buffing element having a plurality of discrete buffing members comprising a step 1) of providing a unitary buffing element comprising the plurality of discrete buffing members wherein each discrete buffing member has a surface area of less than the surface area of the semiconductor wafer being finished, each discrete buffing member has a discrete buffing member buffing surface and a buffing member body, each discrete buffing member has a buffing surface, and each buffing member body is comprised of a continuous region of polymer; a unitary resilient body comprised of an organic polymer and wherein the unitary resilient body having the plurality of separate and distinct buffing members attached to the unitary resilient body; a step 2) of positioning the semiconductor wafer surface proximate to the unitary buffing element; a step 3) of applying an operative buffing motion with a buffing pressure between the semiconductor wafer surface and the discrete buffing members; and a step 4) of buffing the semiconductor wafer surface.
A preferred embodiment of this invention is directed to a process for refining a semiconductor wafer surface with a multiphase polymeric composition, the multiphase polymeric composition comprising a multiphase synthetic polymer composition having a continuous phase of synthetic polymer xe2x80x9cAxe2x80x9d and a synthetic polymer xe2x80x9cBxe2x80x9d and wherein the multiphase composition has at least two distinct glass transition temperatures; and a compatibilizing polymer xe2x80x9cCxe2x80x9d; and the process for refining comprises a step 1) of applying the multiphase polymeric composition to a semiconductor wafer surface; and a step 2) of operatively refining a semiconductor wafer surface with the multiphase polymeric composition.
A preferred embodiment of this invention is directed to a process for refining a semiconductor wafer surface with an multiphase polymeric composition, the multiphase polymeric composition comprising a multiphase synthetic polymer composition comprising a first polymer and a second polymer; at least one of the first or second polymer precleaned by undergoing a precleaning which removes material capable of scratching a semiconductor wafer surface, the precleaing done before adding the precleaned polymer to the multiphase polymeric composition; and the process for refining comprising a step 1) of applying the multiphase polymeric composition to a semiconductor wafer surface; and a step 2) of operatively refining the semiconductor wafer surface with the multiphase polymeric composition.
A preferred embodiment of this invention is directed to a process for refining a semiconductor wafer surface with an multiphase polymeric composition, the multiphase polymeric composition comprising a multiphase synthetic polymer composition comprising a first polymer and a second polymer; at least one of the first or second polymers comprising a filtered polymer by undergoing a filtering which removes particles capable of scratching a semiconductor wafer surface, the filtering done before adding the filtered polymer to the multiphase polymeric composition; and the process for refining comprising a step 1) of applying the multiphase polymeric composition to a semiconductor wafer surface; and a step 2) of operatively refining the semiconductor wafer surface with the multiphase polymeric composition.
A preferred embodiment of this invention is directed to a unitary finishing element having a plurality of discrete finishing members for finishing a semiconductor wafer comprising discrete finishing members wherein each discrete finishing member has a surface area of less than the surface area of the semiconductor wafer being finished, each discrete finishing member has a discrete finishing member finishing surface and a finishing member body, each discrete finishing member has an finishing surface, each finishing member body is comprised of a continuous region of stiff organic synthetic resin, and a ratio of the shortest distance across in centimeters of the discrete finishing member body to the thickness in centimeters of the discrete finishing member body is at least 10/1; a unitary resilient body comprised of an organic polymer and the unitary resilient body having a plurality of discrete finishing member fixedly attached to the unitary resilient body in a manner that each discrete finishing member is separate from its nearest discrete finishing member; and the unitary resilient body of organic polymer having a lower flexural modulus than the stiff organic synthetic resin in the finishing member body.
A preferred embodiment of this invention is directed to a process for chemical mechanical finishing with a multiphase polymeric composition, the multiphase polymeric composition comprising a multiphase synthetic polymer composition having a continuous phase of thermoplastic synthetic polymer xe2x80x9cAxe2x80x9d and a synthetic polymer xe2x80x9cBxe2x80x9d and wherein the multiphase composition has at least two distinct glass transition temperatures, and a compatibilizing polymer xe2x80x9cCxe2x80x9d; and the process for chemical mechanical finishing comprising a step 1) of applying the multiphase polymeric composition to a semiconductor wafer surface; and a step 2) of operatively finishing a semiconductor wafer with the multiphase polymeric composition.
A preferred embodiment of this invention is directed to a process for chemical mechanical finishing with an multiphase polymeric composition, the multiphase polymeric composition comprising a multiphase synthetic polymer composition having at least one filtered polymer which removes particles having a maximum dimension of at least 20 microns capable of scratching a semiconductor wafer surface, the filtering done before adding the filtered polymer to the multiphase polymeric composition; and the process for chemical mechanical finishing comprising a step 1) of applying the multiphase polymeric composition to a semiconductor wafer surface; and a step 2) of operatively finishing a semiconductor wafer with the multiphase polymeric composition.
Other preferred embodiments of my invention are described herein.